Application - Order Management
Entity - the two of interest to you are order header and order line

You need to add a new constraint for each.

Constraints Block
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Operation = Update
Attribute = Leave as null (this means any change to any attribute will force a version change).
User Action = pick from 'Generate Version' or 'Generate Version And Require Reason'.
Applies to = leave as null

Conditions block
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Group # = 101
Scope = Any
Validation Entity = Order Header or Order Line
Record Set = Order or line
Not = leave unchecked
Validation Template = Booked
Enabled = Checked
User Message = Required but not displayed. I just put dummy text in here.

The version number on the order header and line can be displayed through the folder tools. Initial version is 0 and goes up by 1 for each change you make. I've checked this set up on my R12 instance and it works fine.